Headworks Rebuild At San Francisco's Largest Wastewater Facility Wins Water Environment Federation Project Excellence Award

Headworks modernization strengthens infrastructure while supporting neighborhood quality of life

The San Francisco Public Utilities Commission's (SFPUC) $717M new Headworks Facility has earned a Water Environment Federation (WEF) Project Excellence Award for modernizing the Southeast Treatment Plant, without interrupting operations at the city's oldest and largest wastewater facility.

Built in 1952, the Southeast Treatment Plant serves nearly two-thirds of San Francisco's population and treats 80 percent of the city's total annual wastewater flow.

The facility’s aging headworks, which filtered debris and grit from incoming flows, had exceeded their useful life. They were no longer meeting SFPUC’s performance standards for odor control, debris and grit removal, and process reliability -- all critical needs for a combined sewer system that manages both stormwater and wastewater flows.

Effective fine grit removal became especially important with the construction of new digestion and solids-handling processes at the plant, which are highly sensitive to grit contamination.

The project represents a collaborative effort between SFPUC as owner, Carollo Engineers as lead designer, and the Sundt-Walsh Joint Venture as construction manager and general contractor. This alternative delivery structure enabled accelerated scheduling and real-time cost management while achieving the highest standards of quality and sustainability.

The team successfully delivered a state-of-the-art, all-weather, 250-million-gallons-per-day headworks facility featuring a space-saving vertical design. The project overcame unprecedented challenges, including the COVID-19 pandemic, site footprint constraints, and grit loads exceeding ten times typical industry standards.

“This project represents a landmark achievement that reflects the SFPUC's commitment to being a good neighbor and working in harmony with environmental and community interests," said SFPUC Project Manager Jignesh Desai. "As we modernize our critical wastewater facilities, we are leveraging these investments to support both community and the environment – people and place. The upgraded Southeast Treatment Plant demonstrates how innovative engineering and construction can create infrastructure that serves current needs while building future resilience.”

Key technical achievements include advanced screening systems that capture increased debris levels with half of the originally planned channels, a comprehensive odor control system that significantly reduces impacts on the surrounding Bayview neighborhood, and a best-in-class grit removal, washing, and dewatering system. This system separates organic and inert materials, significantly reducing landfill waste and enhancing readiness for advanced digestion technologies that will bring greater environmental benefits in the future.

When the original plan to replace an aging pump station became financially unfeasible, the team pivoted to an extensive rehabilitation approach that saved significant costs while achieving seismic resilience standards.

"The team's ability to adapt and innovate during unforeseen circumstances exemplifies excellence in collaborative project delivery," said Carollo Project Director Jim Hagstrom. "The unified partnership between owner, designer, and construction teams, even while navigating remote work constraints, enabled us to deliver exceptional infrastructure that will serve San Francisco for generations."

The facility is designed to withstand earthquakes up to 7.8 magnitude and accommodate 36 inches of projected sea level rise by 2100. Sustainability features include strategically placed windows and skylights to maximize natural light, energy-efficient LED fixtures, photocell-controlled exterior lighting to minimize energy use during inactive periods, and roof-mounted photovoltaic panels to harness solar energy and convert it into electricity.

Previously, the project became the first wastewater headworks project in the country, and the first project for the City and County of San Francisco, to earn Envision Gold from the Institute for Sustainable Infrastructure, underscoring SFPUC’s commitment to sustainability and community impact.

Beyond technical accomplishments, the project enhanced community integration through odor control improvements and public art installations, including a 335-foot-long by 35-foot-high mural by renowned artist Norie Sato.

“The project's approaches to space-constrained construction, extreme grit handling, and community engagement provide a blueprint for how essential infrastructure can address environmental challenges, build resilience to changing weather patterns, and enhance community well-being,” said Sundt-Walsh Project Director Sam Reidy.

About The San Francisco Public Utilities Commission
The San Francisco Public Utilities Commission is a department of the City and County of San Francisco. It delivers drinking water to 2.7 million people in the San Francisco Bay Area, collects and treats wastewater for the City and County of San Francisco, and meets 75% of the electricity demand in San Francisco. The SFPUC’s mission is to provide customers with high-quality, efficient and reliable water, power, and sewer services in a manner that values environmental and community interests, and sustains the resources entrusted to the agency's care. For more information, visit https://www.sfpuc.gov/

About Carollo Engineers
For over 90 years, Carollo Engineers has provided a full range of innovative planning, design, and construction management services to address the water needs of municipalities, public agencies, private developers, and industrial clients. Carollo develops robust water management strategies that leverage collaboration, provide multi-benefit solutions, and achieve sustainability and resilience. Carollo has over 1,700 employees located across North America. For more information, visit https://carollo.com/.